şifer

/ʃifer/

Cases

SingularPluralWhen to use it
nominativeşiferthe slateşiferlethe slatesthe plain dictionary form — the doer of the sentence
genitiveşifernithe slate'sşiferlenithe slates'the owner — whose it is
accusativeşifernithe slate (as the object)şiferlenithe slates (as the object)a specific, known object — whom or what
dativeşifergeto the slateşiferlegeto the slatesdirection or recipient — to where, to whom
locativeşiferdeat / in the slateşiferledeat / in the slateswhere it is; also having — mende bar, "I have it"
ablativeşiferdenfrom the slateşiferledenfrom the slateswhere it comes from; also "than" when comparing
When to use each case
nominative
the plain dictionary form — the doer of the sentence
genitive
the owner — whose it is
accusative
a specific, known object — whom or what
dative
direction or recipient — to where, to whom
locative
where it is; also having — mende bar, "I have it"
ablative
where it comes from; also "than" when comparing

The endings are the same ones the pronouns wear — that page explains when each case is used.

With an owner

One ownedSeveral owned
myşiferimmy slateşiferlerimmy slates
yourşiferingyour slateşiferleringyour slates
his / herşiferihis / her slateşiferlerihis / her slates
ourşiferibizour slateşiferleribizour slates
you all'sşiferigizyou all's slateşiferlerigizyou all's slates
theirşiferleritheir slateşiferleritheir slates

The overlap in the last rows is real, not a mistake: şiferleri can mean "his / her slates", "their slate", or "their slates" — context decides.